Such a protective device serves to prevent, in the case of a lateral impact, contact between the vehicle occupant and parts of the vehicle such as the B column or the inner side of the door or with movable or stationary objects like other vehicles or posts, intruding into the vehicle. One problem with such protective devices is that the head protecting gas bag must be exactly and reliably positioned so that even if the impact of the vehicle occupant's head is not exactly central there will be no displacement of the head out of a position ensuring proper protection. A further problem is in connection with the safety belt which normally extends from the B column to the upper body of the vehicle occupant and which may obstruct deployment of the head protecting gas bag.